Most viewers who love “movies about movies” will probably enjoy Tropic Thunder. Director, co-writer and star Ben Stiller pulls out all the stops in this loud, outrageous spoof of Hollywood blockbusters. I’m still chuckling over some of the film’s hilarious scenes -- but also cringing whenever I think about its heavy reliance on extremely crude language and all those disparaging references to “retards.”

Three actors (Stiller, Jack Black, Robert Downey Jr.) are in the midst of filming an action movie when their director (Steve Coogan) decides to thrust them into a real warlike situation. Naturally, chaos ensues. Stiller (Night at the Museum) plays Tugg Speedman, whose claim to fame comes from the many Rambo-like films he’s made, and Black (Nacho Libre) is Jeff Portnoy, a flatulence comic who goes wild when a jungle bird steals his “jelly beans.” But the class acting here comes from Downey Jr. (Iron Man) as a multi-talented Australian thespian who undergoes “skin pigmentation” to portray an African-American soldier in the film. Downey’s vocal inflections, physical appearance and body language change completely with each character -- and he’s absolutely amazing! When will this guy receive an Oscar? Not soon enough for me.

While all three of the main actors in Tropic Thunder succeed in evoking plenty of laughter, especially in terms of depicting the self-absorbed nature of Hollywood celebrities, Jack Black ends up at the bottom of the humor chain. His character is the most unlikable and spends a great deal of time yelling and breaking wind. That’s too bad, because he’s one of the best funnymen around.

Surprisingly, the biggest laughs at the screening I attended came when little Brandon Soo Hoo (from TV’s Sesame Street) took charge of things as the leader of a ruthless heroin gang that kidnaps one of the stars. Soo Hoo simply delighted me as his character struggled between angry intensity and movie fan excitement. 

Next in line? An unrecognizable Tom Cruise (War of the Worlds) as Leo Grossman (he really is a gross man here), an unscrupulous movie bigwig. Cruise wowed me in this weird role, one I would never have expected him to take on. The rest of the supporting cast members also deliver fine performances. Nick Nolte (Hulk), playing the “hero” author of the book being filmed, looks appropriately seedy and growls at everyone as only he can do. Jay Baruchel (Knocked Up) and Brandon T. Jackson (This Christmas) blend in nicely as the two lesser-known -- and more reasonable -- actors in the movie being shot. Matthew McConaughey (We Are Marshall) is fun to watch as a fast-talking agent trying to decide whether to choose money or the safety of his client, and Danny McBride (The Foot Fist Way), portraying an overly confident crew member, makes the most of his limited time on camera.        

Massive explosions, bloody battle scenes -- both fake and real -- plus lots of firepower fill the screen, so don’t expect anything subtle here. Instead, prepare yourself for a sledgehammer skewering aimed at some of Hollywood’s most offensive practices, including phoniness and those awful trailers. It’s a dirty job, but someone had to do it.    

(Released by DreamWorks and rated “R” for pervasive language including sexual references, violent content and drug material.)